A major limitation of current techniques to culture epithelial cells in vitro is that the cells rest on plastic, rather than on a basement lamina or within a tissue matrix. Because 85-90% of human malignancies are carcinomas, it is of prime importance to develop normal and malignant culture models of human epithelial cells capable of expressing their in vivo characteristics. The proposed research focuses on a routine use of the extracellular matrix (ECM) produced by cultured corneal or vascular endothelial cells as a naturally produced substrate most adequate for sustaining growth and differentiation of human epithelial cells. Our preliminary study suggest that this ECM by virture of closely resembling naturally occurring basement membranes, exerts a permissive effect leading to enhanced growth of human epithelial cells is vitro and to a better cellular response to physiologically occurring hormones and growth factors. The main objectives of the proposed research are to develop a reliable culture techniques for the isolation and long term maintenance of human epithelial cells, whether normal or malignant, obtained from fresh surgical biopsy material and from previously established human cell lines and compare various aspects of growth characteristics, morphological appearance, cell surface properties and metabolic behavior of cells maintained on ECM vs. on plastic. The possibility that cells maintained on ECM will better resemble their in vivo counterparts will be tested. In addition, structural requirements for the induction of cell attachment, migration, proliferation and differentiation by the ECM will be analyzed by modifying the ECM and studying the associated effects on its ability to support the growth of cells placed in contact with it. We shall also attempt to investigate some aspects of the mechanisms and specificity of tumor cell metastasis, by studying the ability of human tumor cells to attach to vascular endothelial cells and subsequently invade and degrade its underlying ECM. Finally, the feasibility of an in vitro, colony survival, predictive assay to test the sensitivity of human normal and tumor cells to radiation and anticancer drugs, and its potential clinical use in cancer therapy will also be investigated.